Those version checks are if renego tried to change the version, but at that
point we're out of the initial null cipher and should leave the version fixed.

(On the server end, the code in question was dead after the version negotiation
rewrite anyway.)

Change-Id: I3242ba11bc9981ccf7fdb867176d59846cc49dd9
Reviewed-on: https://boringssl-review.googlesource.com/2605
Reviewed-by: Adam Langley <agl@google.com>